The health display works, and the player sustains damage several different ways now...
- Health degrades slowly while underwater.
- Crashing at high speed or falling at high-speed causes 10% damage.
- Colliding with an Orb causes 20% damage.

I didn't make it too difficult because I still want the game to be a relaxing experience. But it seems like a requirement to have health in this kind of game and adds a little more variety.